1. Field of the Invention
The present invention relates to a resin composition useful for thin-wall molded products such as integrated circuit (IC) cards, playing cards, and floppy disks; structural components for office-automation appliances, communications equipment such as portable phones, and household electrical appliances; and automobile parts. More particularly, the present invention relates to an impact-resistant resin composition which comprises a polycarbonate resin and a polyester resin as main components thereof and which has improved impact resistance through the aid of an added specific epoxy-modified block copolymer, and to a molded product obtained by molding the resin composition.
2. Background of the Invention
It has recently been thought that electronic-commerce cards (electronic money) will be rapidly developed and put into full-scale practical use in the near future. Heretofore, polyvinyl-based materials have been used for manufacturing cards; however, it is assumed that substitution for polyvinyl resin will be strongly promoted due to the environmental problem of dioxin.
Plastic cards have a thickness as thin as 1 mm or less, and material used in production thereof requires high fluidity and impact resistance. ABS resin, polycarbonate resin, polybutylene terephthalate, and polyethylene terephthalate resins have been developed as a substitute for vinyl chloride; however, these resins have never combined high fluidity with high impact resistance. In an effort to improve the impact resistance, a method of adding elastomer to these resins has been tested; however, the elastomer suffers the problem of lacking affinity and dispersibility to the resins.
In view of the foregoing, the present inventors have disclosed in Japanese Patent Application Laid-Open (kokai) No. 25984/1995 an epoxy-modified block polymer or a partially-hydrogenated-epoxy-modified block polymer which is useful as an impact-resistance enhancer.
U.S. Pat. No. 2,676,525 discloses a composition which is obtained by dispersing a modified hydrogenated block copolymer (b) obtained by the following method in a thermoplastic resin (a) including polycarbonate resin, or polycarbonate resin and polyester resin. The modified hydrogenated block copolymer (b) is obtained by grafting a glycidyl-group-containing unsaturated compound to a hydrogenated block copolymer obtained by partially hydrogenating an aliphatic double bond based on a conjugated diene compound of a block copolymer including a conjugated diene and a vinyl-group-containing aromatic hydrocarbon. However, the glycidyl-group-modified hydrogenated block copolymer (b) which is used herein involves the problem of being likely to gel due to heat applied in the manufacturing process thereof and in the process of producing molded products therefrom.
Japanese Patent Application Laid-Open (kokai) No. 157504/1997 discloses a hydrogenated or nonhydrogenated block copolymer modified with an ethylenic-unsaturated-group-containing carboxylic acid (e.g. maleic anhydride) or derivatives thereof.
Japanese Patent Application Laid-Open (kokai) No. 48861/1996 discloses a hydrogenated block copolymer modified with an hydroxyl-group-containing .alpha.,.beta.-unsaturated carboxylic acid and an aromatic vinyl compound.
However, the disclosed polymers heretofore do not adequately meet the requirement of high impact resistance and mold-processability, especially for material used for thin-wall molded products such as IC cards.